1. Technical Field of the Invention
The present invention relates to the domain of analog electronic circuits. More particularly, the invention relates to a device and a process for adjustment of an operating parameter of such a circuit. One particularly attractive application of such a device and such a process relates to the adjustment of the reference voltage supplied by a reference voltage source.
2. Description of Related Art
A reference voltage source is an analog circuit that outputs a constant voltage independent of the operating temperature and the applied power supply current.
As it is conceived, the value of the voltage output by the reference voltage source is a parameter that has to be fixed very precisely. However during assembly, and particularly when the circuit is packaged, the voltage output by the circuit may drift significantly.
Reference voltage sources are provided with an adjustment device, for example a device integrated into one of the stages of the source, to compensate for this drift. This adjustment device acts by adapting the global value of resistances placed between the anode and the cathode of the circuit as a function of the voltage to be adjusted, using fusible elements that can be selectively activated.
The voltage output by the analog circuit is adjusted by selecting one or several fusible elements and by applying a sufficiently high voltage to these elements so that they break down.
These fusible elements are selected and activated using specific pins, each of which communicates with one of the fusible elements.
Thus, electronic circuits of this type do not have a standard configuration, to the extent that they include additional pins.
Furthermore, the parameter is adjusted before packaging, in other words before the parameter to be adjusted is affected by a drift. Therefore, this adjustment is made in advance and is necessarily imperfect.
There is a need to overcome these disadvantages and to provide a device and a method for adjusting an operating parameter of an analog circuit that can be integrated into a standard analog circuit and that is capable of compensating for the drift of the parameter during packaging, with improved precision.